A Pilot Randomized Trial of Financial Incentives or Coaching to Lower Serum Phosphorus in Dialysis Patients

Abstract

Among chronic hemodialysis patients, hyperphosphatemia is common and associated with mortality. Behavioral economics and complementary behavior-change theories may offer valuable approaches to achieving phosphorus (PO4) control. The aim was to determine feasibility of implementing financial incentives and structured coaching to improve PO4 in the hemodialysis setting. This pilot randomized controlled trial was conducted in 3 urban dialysis units for 10weeks among 36 adults with elevated serum PO4 (median >5.5mg/dL over 3months). Twelve participants each were randomized to: (1) financial incentives for lowering PO4, (2) coaching about dietary and medication adherence, or (3) usual care. PO4 was measured during routine clinic operations. Each incentives arm participant received the equivalent of $1.50/day if the PO4 was ≤5.5mg/dL or >5.5mg/dL but decreased ≥0.5mg/dL since the prior measurement. The coach was instructed to contact coaching arm participants at least 3 times per week. The outcome measures included: (1) enrollment rate, (2) dropout rate, and (3) change in PO4 from beginning to end of 10-week intervention period. Of 66 eligible patients, 36 (55%) enrolled. Median age was 53years, 83% were black race, and 78% were male. Median baseline PO4 was 6.0 (interquartile range 5.6, 7.5). Using stratified generalized estimation equation analyses, the monthly decline in PO4 was -0.32mg/dL (95% CI -0.60, -0.04) in the incentives arm, -0.40mg/dL (-0.60, -0.20) in the coaching arm, and -0.24mg/dL (-0.60, 0.08) in the usual care arm. No patients dropped out. All intervention arm participants expressed interest in receiving similar support in the future. This pilot trial demonstrated good feasibility in enrollment and implementation of novel behavioral health strategies to reduce PO4 in dialysis patients.